V4L/DVB (4506): TVP5150 routing logic were broken.
[linux-2.6] / drivers / md / bitmap.c
1 /*
2  * bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
3  *
4  * bitmap_create  - sets up the bitmap structure
5  * bitmap_destroy - destroys the bitmap structure
6  *
7  * additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
8  * - added disk storage for bitmap
9  * - changes to allow various bitmap chunk sizes
10  */
11
12 /*
13  * Still to do:
14  *
15  * flush after percent set rather than just time based. (maybe both).
16  * wait if count gets too high, wake when it drops to half.
17  */
18
19 #include <linux/module.h>
20 #include <linux/errno.h>
21 #include <linux/slab.h>
22 #include <linux/init.h>
23 #include <linux/timer.h>
24 #include <linux/sched.h>
25 #include <linux/list.h>
26 #include <linux/file.h>
27 #include <linux/mount.h>
28 #include <linux/buffer_head.h>
29 #include <linux/raid/md.h>
30 #include <linux/raid/bitmap.h>
31
32 /* debug macros */
33
34 #define DEBUG 0
35
36 #if DEBUG
37 /* these are for debugging purposes only! */
38
39 /* define one and only one of these */
40 #define INJECT_FAULTS_1 0 /* cause bitmap_alloc_page to fail always */
41 #define INJECT_FAULTS_2 0 /* cause bitmap file to be kicked when first bit set*/
42 #define INJECT_FAULTS_3 0 /* treat bitmap file as kicked at init time */
43 #define INJECT_FAULTS_4 0 /* undef */
44 #define INJECT_FAULTS_5 0 /* undef */
45 #define INJECT_FAULTS_6 0
46
47 /* if these are defined, the driver will fail! debug only */
48 #define INJECT_FATAL_FAULT_1 0 /* fail kmalloc, causing bitmap_create to fail */
49 #define INJECT_FATAL_FAULT_2 0 /* undef */
50 #define INJECT_FATAL_FAULT_3 0 /* undef */
51 #endif
52
53 //#define DPRINTK PRINTK /* set this NULL to avoid verbose debug output */
54 #define DPRINTK(x...) do { } while(0)
55
56 #ifndef PRINTK
57 #  if DEBUG > 0
58 #    define PRINTK(x...) printk(KERN_DEBUG x)
59 #  else
60 #    define PRINTK(x...)
61 #  endif
62 #endif
63
64 static inline char * bmname(struct bitmap *bitmap)
65 {
66         return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
67 }
68
69
70 /*
71  * just a placeholder - calls kmalloc for bitmap pages
72  */
73 static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
74 {
75         unsigned char *page;
76
77 #ifdef INJECT_FAULTS_1
78         page = NULL;
79 #else
80         page = kmalloc(PAGE_SIZE, GFP_NOIO);
81 #endif
82         if (!page)
83                 printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
84         else
85                 PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
86                         bmname(bitmap), page);
87         return page;
88 }
89
90 /*
91  * for now just a placeholder -- just calls kfree for bitmap pages
92  */
93 static void bitmap_free_page(struct bitmap *bitmap, unsigned char *page)
94 {
95         PRINTK("%s: bitmap_free_page: free page %p\n", bmname(bitmap), page);
96         kfree(page);
97 }
98
99 /*
100  * check a page and, if necessary, allocate it (or hijack it if the alloc fails)
101  *
102  * 1) check to see if this page is allocated, if it's not then try to alloc
103  * 2) if the alloc fails, set the page's hijacked flag so we'll use the
104  *    page pointer directly as a counter
105  *
106  * if we find our page, we increment the page's refcount so that it stays
107  * allocated while we're using it
108  */
109 static int bitmap_checkpage(struct bitmap *bitmap, unsigned long page, int create)
110 {
111         unsigned char *mappage;
112
113         if (page >= bitmap->pages) {
114                 printk(KERN_ALERT
115                         "%s: invalid bitmap page request: %lu (> %lu)\n",
116                         bmname(bitmap), page, bitmap->pages-1);
117                 return -EINVAL;
118         }
119
120
121         if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
122                 return 0;
123
124         if (bitmap->bp[page].map) /* page is already allocated, just return */
125                 return 0;
126
127         if (!create)
128                 return -ENOENT;
129
130         spin_unlock_irq(&bitmap->lock);
131
132         /* this page has not been allocated yet */
133
134         if ((mappage = bitmap_alloc_page(bitmap)) == NULL) {
135                 PRINTK("%s: bitmap map page allocation failed, hijacking\n",
136                         bmname(bitmap));
137                 /* failed - set the hijacked flag so that we can use the
138                  * pointer as a counter */
139                 spin_lock_irq(&bitmap->lock);
140                 if (!bitmap->bp[page].map)
141                         bitmap->bp[page].hijacked = 1;
142                 goto out;
143         }
144
145         /* got a page */
146
147         spin_lock_irq(&bitmap->lock);
148
149         /* recheck the page */
150
151         if (bitmap->bp[page].map || bitmap->bp[page].hijacked) {
152                 /* somebody beat us to getting the page */
153                 bitmap_free_page(bitmap, mappage);
154                 return 0;
155         }
156
157         /* no page was in place and we have one, so install it */
158
159         memset(mappage, 0, PAGE_SIZE);
160         bitmap->bp[page].map = mappage;
161         bitmap->missing_pages--;
162 out:
163         return 0;
164 }
165
166
167 /* if page is completely empty, put it back on the free list, or dealloc it */
168 /* if page was hijacked, unmark the flag so it might get alloced next time */
169 /* Note: lock should be held when calling this */
170 static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
171 {
172         char *ptr;
173
174         if (bitmap->bp[page].count) /* page is still busy */
175                 return;
176
177         /* page is no longer in use, it can be released */
178
179         if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
180                 bitmap->bp[page].hijacked = 0;
181                 bitmap->bp[page].map = NULL;
182                 return;
183         }
184
185         /* normal case, free the page */
186
187 #if 0
188 /* actually ... let's not.  We will probably need the page again exactly when
189  * memory is tight and we are flusing to disk
190  */
191         return;
192 #else
193         ptr = bitmap->bp[page].map;
194         bitmap->bp[page].map = NULL;
195         bitmap->missing_pages++;
196         bitmap_free_page(bitmap, ptr);
197         return;
198 #endif
199 }
200
201
202 /*
203  * bitmap file handling - read and write the bitmap file and its superblock
204  */
205
206 /* copy the pathname of a file to a buffer */
207 char *file_path(struct file *file, char *buf, int count)
208 {
209         struct dentry *d;
210         struct vfsmount *v;
211
212         if (!buf)
213                 return NULL;
214
215         d = file->f_dentry;
216         v = file->f_vfsmnt;
217
218         buf = d_path(d, v, buf, count);
219
220         return IS_ERR(buf) ? NULL : buf;
221 }
222
223 /*
224  * basic page I/O operations
225  */
226
227 /* IO operations when bitmap is stored near all superblocks */
228 static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
229 {
230         /* choose a good rdev and read the page from there */
231
232         mdk_rdev_t *rdev;
233         struct list_head *tmp;
234         struct page *page = alloc_page(GFP_KERNEL);
235         sector_t target;
236
237         if (!page)
238                 return ERR_PTR(-ENOMEM);
239
240         ITERATE_RDEV(mddev, rdev, tmp) {
241                 if (! test_bit(In_sync, &rdev->flags)
242                     || test_bit(Faulty, &rdev->flags))
243                         continue;
244
245                 target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
246
247                 if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {
248                         page->index = index;
249                         attach_page_buffers(page, NULL); /* so that free_buffer will
250                                                           * quietly no-op */
251                         return page;
252                 }
253         }
254         return ERR_PTR(-EIO);
255
256 }
257
258 static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
259 {
260         mdk_rdev_t *rdev;
261         struct list_head *tmp;
262
263         ITERATE_RDEV(mddev, rdev, tmp)
264                 if (test_bit(In_sync, &rdev->flags)
265                     && !test_bit(Faulty, &rdev->flags))
266                         md_super_write(mddev, rdev,
267                                        (rdev->sb_offset<<1) + offset
268                                        + page->index * (PAGE_SIZE/512),
269                                        PAGE_SIZE,
270                                        page);
271
272         if (wait)
273                 md_super_wait(mddev);
274         return 0;
275 }
276
277 /*
278  * write out a page to a file
279  */
280 static int write_page(struct bitmap *bitmap, struct page *page, int wait)
281 {
282         struct buffer_head *bh;
283
284         if (bitmap->file == NULL)
285                 return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
286
287         bh = page_buffers(page);
288
289         while (bh && bh->b_blocknr) {
290                 atomic_inc(&bitmap->pending_writes);
291                 set_buffer_locked(bh);
292                 set_buffer_mapped(bh);
293                 submit_bh(WRITE, bh);
294                 bh = bh->b_this_page;
295         }
296
297         if (wait) {
298                 wait_event(bitmap->write_wait,
299                            atomic_read(&bitmap->pending_writes)==0);
300                 return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
301         }
302         return 0;
303 }
304
305 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
306 {
307         struct bitmap *bitmap = bh->b_private;
308         unsigned long flags;
309
310         if (!uptodate) {
311                 spin_lock_irqsave(&bitmap->lock, flags);
312                 bitmap->flags |= BITMAP_WRITE_ERROR;
313                 spin_unlock_irqrestore(&bitmap->lock, flags);
314         }
315         if (atomic_dec_and_test(&bitmap->pending_writes))
316                 wake_up(&bitmap->write_wait);
317 }
318
319 /* copied from buffer.c */
320 static void
321 __clear_page_buffers(struct page *page)
322 {
323         ClearPagePrivate(page);
324         set_page_private(page, 0);
325         page_cache_release(page);
326 }
327 static void free_buffers(struct page *page)
328 {
329         struct buffer_head *bh = page_buffers(page);
330
331         while (bh) {
332                 struct buffer_head *next = bh->b_this_page;
333                 free_buffer_head(bh);
334                 bh = next;
335         }
336         __clear_page_buffers(page);
337         put_page(page);
338 }
339
340 /* read a page from a file.
341  * We both read the page, and attach buffers to the page to record the
342  * address of each block (using bmap).  These addresses will be used
343  * to write the block later, completely bypassing the filesystem.
344  * This usage is similar to how swap files are handled, and allows us
345  * to write to a file with no concerns of memory allocation failing.
346  */
347 static struct page *read_page(struct file *file, unsigned long index,
348                               struct bitmap *bitmap,
349                               unsigned long count)
350 {
351         struct page *page = NULL;
352         struct inode *inode = file->f_dentry->d_inode;
353         struct buffer_head *bh;
354         sector_t block;
355
356         PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
357                         (unsigned long long)index << PAGE_SHIFT);
358
359         page = alloc_page(GFP_KERNEL);
360         if (!page)
361                 page = ERR_PTR(-ENOMEM);
362         if (IS_ERR(page))
363                 goto out;
364
365         bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
366         if (!bh) {
367                 put_page(page);
368                 page = ERR_PTR(-ENOMEM);
369                 goto out;
370         }
371         attach_page_buffers(page, bh);
372         block = index << (PAGE_SHIFT - inode->i_blkbits);
373         while (bh) {
374                 if (count == 0)
375                         bh->b_blocknr = 0;
376                 else {
377                         bh->b_blocknr = bmap(inode, block);
378                         if (bh->b_blocknr == 0) {
379                                 /* Cannot use this file! */
380                                 free_buffers(page);
381                                 page = ERR_PTR(-EINVAL);
382                                 goto out;
383                         }
384                         bh->b_bdev = inode->i_sb->s_bdev;
385                         if (count < (1<<inode->i_blkbits))
386                                 count = 0;
387                         else
388                                 count -= (1<<inode->i_blkbits);
389
390                         bh->b_end_io = end_bitmap_write;
391                         bh->b_private = bitmap;
392                         atomic_inc(&bitmap->pending_writes);
393                         set_buffer_locked(bh);
394                         set_buffer_mapped(bh);
395                         submit_bh(READ, bh);
396                 }
397                 block++;
398                 bh = bh->b_this_page;
399         }
400         page->index = index;
401
402         wait_event(bitmap->write_wait,
403                    atomic_read(&bitmap->pending_writes)==0);
404         if (bitmap->flags & BITMAP_WRITE_ERROR) {
405                 free_buffers(page);
406                 page = ERR_PTR(-EIO);
407         }
408 out:
409         if (IS_ERR(page))
410                 printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
411                         (int)PAGE_SIZE,
412                         (unsigned long long)index << PAGE_SHIFT,
413                         PTR_ERR(page));
414         return page;
415 }
416
417 /*
418  * bitmap file superblock operations
419  */
420
421 /* update the event counter and sync the superblock to disk */
422 int bitmap_update_sb(struct bitmap *bitmap)
423 {
424         bitmap_super_t *sb;
425         unsigned long flags;
426
427         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
428                 return 0;
429         spin_lock_irqsave(&bitmap->lock, flags);
430         if (!bitmap->sb_page) { /* no superblock */
431                 spin_unlock_irqrestore(&bitmap->lock, flags);
432                 return 0;
433         }
434         spin_unlock_irqrestore(&bitmap->lock, flags);
435         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
436         sb->events = cpu_to_le64(bitmap->mddev->events);
437         if (!bitmap->mddev->degraded)
438                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
439         kunmap_atomic(sb, KM_USER0);
440         return write_page(bitmap, bitmap->sb_page, 1);
441 }
442
443 /* print out the bitmap file superblock */
444 void bitmap_print_sb(struct bitmap *bitmap)
445 {
446         bitmap_super_t *sb;
447
448         if (!bitmap || !bitmap->sb_page)
449                 return;
450         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
451         printk(KERN_DEBUG "%s: bitmap file superblock:\n", bmname(bitmap));
452         printk(KERN_DEBUG "         magic: %08x\n", le32_to_cpu(sb->magic));
453         printk(KERN_DEBUG "       version: %d\n", le32_to_cpu(sb->version));
454         printk(KERN_DEBUG "          uuid: %08x.%08x.%08x.%08x\n",
455                                         *(__u32 *)(sb->uuid+0),
456                                         *(__u32 *)(sb->uuid+4),
457                                         *(__u32 *)(sb->uuid+8),
458                                         *(__u32 *)(sb->uuid+12));
459         printk(KERN_DEBUG "        events: %llu\n",
460                         (unsigned long long) le64_to_cpu(sb->events));
461         printk(KERN_DEBUG "events cleared: %llu\n",
462                         (unsigned long long) le64_to_cpu(sb->events_cleared));
463         printk(KERN_DEBUG "         state: %08x\n", le32_to_cpu(sb->state));
464         printk(KERN_DEBUG "     chunksize: %d B\n", le32_to_cpu(sb->chunksize));
465         printk(KERN_DEBUG "  daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
466         printk(KERN_DEBUG "     sync size: %llu KB\n",
467                         (unsigned long long)le64_to_cpu(sb->sync_size)/2);
468         printk(KERN_DEBUG "max write behind: %d\n", le32_to_cpu(sb->write_behind));
469         kunmap_atomic(sb, KM_USER0);
470 }
471
472 /* read the superblock from the bitmap file and initialize some bitmap fields */
473 static int bitmap_read_sb(struct bitmap *bitmap)
474 {
475         char *reason = NULL;
476         bitmap_super_t *sb;
477         unsigned long chunksize, daemon_sleep, write_behind;
478         unsigned long long events;
479         int err = -EINVAL;
480
481         /* page 0 is the superblock, read it... */
482         if (bitmap->file)
483                 bitmap->sb_page = read_page(bitmap->file, 0, bitmap, PAGE_SIZE);
484         else {
485                 bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
486         }
487         if (IS_ERR(bitmap->sb_page)) {
488                 err = PTR_ERR(bitmap->sb_page);
489                 bitmap->sb_page = NULL;
490                 return err;
491         }
492
493         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
494
495         chunksize = le32_to_cpu(sb->chunksize);
496         daemon_sleep = le32_to_cpu(sb->daemon_sleep);
497         write_behind = le32_to_cpu(sb->write_behind);
498
499         /* verify that the bitmap-specific fields are valid */
500         if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
501                 reason = "bad magic";
502         else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
503                  le32_to_cpu(sb->version) > BITMAP_MAJOR_HI)
504                 reason = "unrecognized superblock version";
505         else if (chunksize < PAGE_SIZE)
506                 reason = "bitmap chunksize too small";
507         else if ((1 << ffz(~chunksize)) != chunksize)
508                 reason = "bitmap chunksize not a power of 2";
509         else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT / HZ)
510                 reason = "daemon sleep period out of range";
511         else if (write_behind > COUNTER_MAX)
512                 reason = "write-behind limit out of range (0 - 16383)";
513         if (reason) {
514                 printk(KERN_INFO "%s: invalid bitmap file superblock: %s\n",
515                         bmname(bitmap), reason);
516                 goto out;
517         }
518
519         /* keep the array size field of the bitmap superblock up to date */
520         sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
521
522         if (!bitmap->mddev->persistent)
523                 goto success;
524
525         /*
526          * if we have a persistent array superblock, compare the
527          * bitmap's UUID and event counter to the mddev's
528          */
529         if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
530                 printk(KERN_INFO "%s: bitmap superblock UUID mismatch\n",
531                         bmname(bitmap));
532                 goto out;
533         }
534         events = le64_to_cpu(sb->events);
535         if (events < bitmap->mddev->events) {
536                 printk(KERN_INFO "%s: bitmap file is out of date (%llu < %llu) "
537                         "-- forcing full recovery\n", bmname(bitmap), events,
538                         (unsigned long long) bitmap->mddev->events);
539                 sb->state |= BITMAP_STALE;
540         }
541 success:
542         /* assign fields using values from superblock */
543         bitmap->chunksize = chunksize;
544         bitmap->daemon_sleep = daemon_sleep;
545         bitmap->daemon_lastrun = jiffies;
546         bitmap->max_write_behind = write_behind;
547         bitmap->flags |= sb->state;
548         if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
549                 bitmap->flags |= BITMAP_HOSTENDIAN;
550         bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
551         if (sb->state & BITMAP_STALE)
552                 bitmap->events_cleared = bitmap->mddev->events;
553         err = 0;
554 out:
555         kunmap_atomic(sb, KM_USER0);
556         if (err)
557                 bitmap_print_sb(bitmap);
558         return err;
559 }
560
561 enum bitmap_mask_op {
562         MASK_SET,
563         MASK_UNSET
564 };
565
566 /* record the state of the bitmap in the superblock */
567 static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
568                                 enum bitmap_mask_op op)
569 {
570         bitmap_super_t *sb;
571         unsigned long flags;
572
573         spin_lock_irqsave(&bitmap->lock, flags);
574         if (!bitmap->sb_page) { /* can't set the state */
575                 spin_unlock_irqrestore(&bitmap->lock, flags);
576                 return;
577         }
578         spin_unlock_irqrestore(&bitmap->lock, flags);
579         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
580         switch (op) {
581                 case MASK_SET: sb->state |= bits;
582                                 break;
583                 case MASK_UNSET: sb->state &= ~bits;
584                                 break;
585                 default: BUG();
586         }
587         kunmap_atomic(sb, KM_USER0);
588 }
589
590 /*
591  * general bitmap file operations
592  */
593
594 /* calculate the index of the page that contains this bit */
595 static inline unsigned long file_page_index(unsigned long chunk)
596 {
597         return CHUNK_BIT_OFFSET(chunk) >> PAGE_BIT_SHIFT;
598 }
599
600 /* calculate the (bit) offset of this bit within a page */
601 static inline unsigned long file_page_offset(unsigned long chunk)
602 {
603         return CHUNK_BIT_OFFSET(chunk) & (PAGE_BITS - 1);
604 }
605
606 /*
607  * return a pointer to the page in the filemap that contains the given bit
608  *
609  * this lookup is complicated by the fact that the bitmap sb might be exactly
610  * 1 page (e.g., x86) or less than 1 page -- so the bitmap might start on page
611  * 0 or page 1
612  */
613 static inline struct page *filemap_get_page(struct bitmap *bitmap,
614                                         unsigned long chunk)
615 {
616         return bitmap->filemap[file_page_index(chunk) - file_page_index(0)];
617 }
618
619
620 static void bitmap_file_unmap(struct bitmap *bitmap)
621 {
622         struct page **map, *sb_page;
623         unsigned long *attr;
624         int pages;
625         unsigned long flags;
626
627         spin_lock_irqsave(&bitmap->lock, flags);
628         map = bitmap->filemap;
629         bitmap->filemap = NULL;
630         attr = bitmap->filemap_attr;
631         bitmap->filemap_attr = NULL;
632         pages = bitmap->file_pages;
633         bitmap->file_pages = 0;
634         sb_page = bitmap->sb_page;
635         bitmap->sb_page = NULL;
636         spin_unlock_irqrestore(&bitmap->lock, flags);
637
638         while (pages--)
639                 if (map[pages]->index != 0) /* 0 is sb_page, release it below */
640                         free_buffers(map[pages]);
641         kfree(map);
642         kfree(attr);
643
644         if (sb_page)
645                 free_buffers(sb_page);
646 }
647
648 static void bitmap_file_put(struct bitmap *bitmap)
649 {
650         struct file *file;
651         unsigned long flags;
652
653         spin_lock_irqsave(&bitmap->lock, flags);
654         file = bitmap->file;
655         bitmap->file = NULL;
656         spin_unlock_irqrestore(&bitmap->lock, flags);
657
658         if (file)
659                 wait_event(bitmap->write_wait,
660                            atomic_read(&bitmap->pending_writes)==0);
661         bitmap_file_unmap(bitmap);
662
663         if (file) {
664                 struct inode *inode = file->f_dentry->d_inode;
665                 invalidate_inode_pages(inode->i_mapping);
666                 fput(file);
667         }
668 }
669
670
671 /*
672  * bitmap_file_kick - if an error occurs while manipulating the bitmap file
673  * then it is no longer reliable, so we stop using it and we mark the file
674  * as failed in the superblock
675  */
676 static void bitmap_file_kick(struct bitmap *bitmap)
677 {
678         char *path, *ptr = NULL;
679
680         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
681         bitmap_update_sb(bitmap);
682
683         if (bitmap->file) {
684                 path = kmalloc(PAGE_SIZE, GFP_KERNEL);
685                 if (path)
686                         ptr = file_path(bitmap->file, path, PAGE_SIZE);
687
688                 printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
689                        bmname(bitmap), ptr ? ptr : "");
690
691                 kfree(path);
692         }
693
694         bitmap_file_put(bitmap);
695
696         return;
697 }
698
699 enum bitmap_page_attr {
700         BITMAP_PAGE_DIRTY = 0, // there are set bits that need to be synced
701         BITMAP_PAGE_CLEAN = 1, // there are bits that might need to be cleared
702         BITMAP_PAGE_NEEDWRITE=2, // there are cleared bits that need to be synced
703 };
704
705 static inline void set_page_attr(struct bitmap *bitmap, struct page *page,
706                                 enum bitmap_page_attr attr)
707 {
708         __set_bit((page->index<<2) + attr, bitmap->filemap_attr);
709 }
710
711 static inline void clear_page_attr(struct bitmap *bitmap, struct page *page,
712                                 enum bitmap_page_attr attr)
713 {
714         __clear_bit((page->index<<2) + attr, bitmap->filemap_attr);
715 }
716
717 static inline unsigned long test_page_attr(struct bitmap *bitmap, struct page *page,
718                                            enum bitmap_page_attr attr)
719 {
720         return test_bit((page->index<<2) + attr, bitmap->filemap_attr);
721 }
722
723 /*
724  * bitmap_file_set_bit -- called before performing a write to the md device
725  * to set (and eventually sync) a particular bit in the bitmap file
726  *
727  * we set the bit immediately, then we record the page number so that
728  * when an unplug occurs, we can flush the dirty pages out to disk
729  */
730 static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
731 {
732         unsigned long bit;
733         struct page *page;
734         void *kaddr;
735         unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
736
737         if (!bitmap->filemap) {
738                 return;
739         }
740
741         page = filemap_get_page(bitmap, chunk);
742         bit = file_page_offset(chunk);
743
744         /* set the bit */
745         kaddr = kmap_atomic(page, KM_USER0);
746         if (bitmap->flags & BITMAP_HOSTENDIAN)
747                 set_bit(bit, kaddr);
748         else
749                 ext2_set_bit(bit, kaddr);
750         kunmap_atomic(kaddr, KM_USER0);
751         PRINTK("set file bit %lu page %lu\n", bit, page->index);
752
753         /* record page number so it gets flushed to disk when unplug occurs */
754         set_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
755
756 }
757
758 /* this gets called when the md device is ready to unplug its underlying
759  * (slave) device queues -- before we let any writes go down, we need to
760  * sync the dirty pages of the bitmap file to disk */
761 int bitmap_unplug(struct bitmap *bitmap)
762 {
763         unsigned long i, flags;
764         int dirty, need_write;
765         struct page *page;
766         int wait = 0;
767         int err;
768
769         if (!bitmap)
770                 return 0;
771
772         /* look at each page to see if there are any set bits that need to be
773          * flushed out to disk */
774         for (i = 0; i < bitmap->file_pages; i++) {
775                 spin_lock_irqsave(&bitmap->lock, flags);
776                 if (!bitmap->filemap) {
777                         spin_unlock_irqrestore(&bitmap->lock, flags);
778                         return 0;
779                 }
780                 page = bitmap->filemap[i];
781                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
782                 need_write = test_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
783                 clear_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
784                 clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
785                 if (dirty)
786                         wait = 1;
787                 spin_unlock_irqrestore(&bitmap->lock, flags);
788
789                 if (dirty | need_write)
790                         err = write_page(bitmap, page, 0);
791         }
792         if (wait) { /* if any writes were performed, we need to wait on them */
793                 if (bitmap->file)
794                         wait_event(bitmap->write_wait,
795                                    atomic_read(&bitmap->pending_writes)==0);
796                 else
797                         md_super_wait(bitmap->mddev);
798         }
799         if (bitmap->flags & BITMAP_WRITE_ERROR)
800                 bitmap_file_kick(bitmap);
801         return 0;
802 }
803
804 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
805 /* * bitmap_init_from_disk -- called at bitmap_create time to initialize
806  * the in-memory bitmap from the on-disk bitmap -- also, sets up the
807  * memory mapping of the bitmap file
808  * Special cases:
809  *   if there's no bitmap file, or if the bitmap file had been
810  *   previously kicked from the array, we mark all the bits as
811  *   1's in order to cause a full resync.
812  *
813  * We ignore all bits for sectors that end earlier than 'start'.
814  * This is used when reading an out-of-date bitmap...
815  */
816 static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
817 {
818         unsigned long i, chunks, index, oldindex, bit;
819         struct page *page = NULL, *oldpage = NULL;
820         unsigned long num_pages, bit_cnt = 0;
821         struct file *file;
822         unsigned long bytes, offset;
823         int outofdate;
824         int ret = -ENOSPC;
825         void *paddr;
826
827         chunks = bitmap->chunks;
828         file = bitmap->file;
829
830         BUG_ON(!file && !bitmap->offset);
831
832 #ifdef INJECT_FAULTS_3
833         outofdate = 1;
834 #else
835         outofdate = bitmap->flags & BITMAP_STALE;
836 #endif
837         if (outofdate)
838                 printk(KERN_INFO "%s: bitmap file is out of date, doing full "
839                         "recovery\n", bmname(bitmap));
840
841         bytes = (chunks + 7) / 8;
842
843         num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
844
845         if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
846                 printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
847                         bmname(bitmap),
848                         (unsigned long) i_size_read(file->f_mapping->host),
849                         bytes + sizeof(bitmap_super_t));
850                 goto out;
851         }
852
853         ret = -ENOMEM;
854
855         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
856         if (!bitmap->filemap)
857                 goto out;
858
859         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
860         bitmap->filemap_attr = kzalloc(
861                 (((num_pages*4/8)+sizeof(unsigned long)-1)
862                  /sizeof(unsigned long))
863                 *sizeof(unsigned long),
864                 GFP_KERNEL);
865         if (!bitmap->filemap_attr)
866                 goto out;
867
868         oldindex = ~0L;
869
870         for (i = 0; i < chunks; i++) {
871                 int b;
872                 index = file_page_index(i);
873                 bit = file_page_offset(i);
874                 if (index != oldindex) { /* this is a new page, read it in */
875                         int count;
876                         /* unmap the old page, we're done with it */
877                         if (index == num_pages-1)
878                                 count = bytes - index * PAGE_SIZE;
879                         else
880                                 count = PAGE_SIZE;
881                         if (index == 0) {
882                                 /*
883                                  * if we're here then the superblock page
884                                  * contains some bits (PAGE_SIZE != sizeof sb)
885                                  * we've already read it in, so just use it
886                                  */
887                                 page = bitmap->sb_page;
888                                 offset = sizeof(bitmap_super_t);
889                         } else if (file) {
890                                 page = read_page(file, index, bitmap, count);
891                                 offset = 0;
892                         } else {
893                                 page = read_sb_page(bitmap->mddev, bitmap->offset, index);
894                                 offset = 0;
895                         }
896                         if (IS_ERR(page)) { /* read error */
897                                 ret = PTR_ERR(page);
898                                 goto out;
899                         }
900
901                         oldindex = index;
902                         oldpage = page;
903
904                         if (outofdate) {
905                                 /*
906                                  * if bitmap is out of date, dirty the
907                                  * whole page and write it out
908                                  */
909                                 paddr = kmap_atomic(page, KM_USER0);
910                                 memset(paddr + offset, 0xff,
911                                        PAGE_SIZE - offset);
912                                 kunmap_atomic(paddr, KM_USER0);
913                                 ret = write_page(bitmap, page, 1);
914                                 if (ret) {
915                                         /* release, page not in filemap yet */
916                                         put_page(page);
917                                         goto out;
918                                 }
919                         }
920
921                         bitmap->filemap[bitmap->file_pages++] = page;
922                 }
923                 paddr = kmap_atomic(page, KM_USER0);
924                 if (bitmap->flags & BITMAP_HOSTENDIAN)
925                         b = test_bit(bit, paddr);
926                 else
927                         b = ext2_test_bit(bit, paddr);
928                 kunmap_atomic(paddr, KM_USER0);
929                 if (b) {
930                         /* if the disk bit is set, set the memory bit */
931                         bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap),
932                                                ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start)
933                                 );
934                         bit_cnt++;
935                         set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
936                 }
937         }
938
939         /* everything went OK */
940         ret = 0;
941         bitmap_mask_state(bitmap, BITMAP_STALE, MASK_UNSET);
942
943         if (bit_cnt) { /* Kick recovery if any bits were set */
944                 set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
945                 md_wakeup_thread(bitmap->mddev->thread);
946         }
947
948 out:
949         printk(KERN_INFO "%s: bitmap initialized from disk: "
950                 "read %lu/%lu pages, set %lu bits, status: %d\n",
951                 bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
952
953         return ret;
954 }
955
956 void bitmap_write_all(struct bitmap *bitmap)
957 {
958         /* We don't actually write all bitmap blocks here,
959          * just flag them as needing to be written
960          */
961         int i;
962
963         for (i=0; i < bitmap->file_pages; i++)
964                 set_page_attr(bitmap, bitmap->filemap[i],
965                               BITMAP_PAGE_NEEDWRITE);
966 }
967
968
969 static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
970 {
971         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
972         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
973         bitmap->bp[page].count += inc;
974 /*
975         if (page == 0) printk("count page 0, offset %llu: %d gives %d\n",
976                               (unsigned long long)offset, inc, bitmap->bp[page].count);
977 */
978         bitmap_checkfree(bitmap, page);
979 }
980 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
981                                             sector_t offset, int *blocks,
982                                             int create);
983
984 /*
985  * bitmap daemon -- periodically wakes up to clean bits and flush pages
986  *                      out to disk
987  */
988
989 int bitmap_daemon_work(struct bitmap *bitmap)
990 {
991         unsigned long j;
992         unsigned long flags;
993         struct page *page = NULL, *lastpage = NULL;
994         int err = 0;
995         int blocks;
996         void *paddr;
997
998         if (bitmap == NULL)
999                 return 0;
1000         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
1001                 return 0;
1002         bitmap->daemon_lastrun = jiffies;
1003
1004         for (j = 0; j < bitmap->chunks; j++) {
1005                 bitmap_counter_t *bmc;
1006                 spin_lock_irqsave(&bitmap->lock, flags);
1007                 if (!bitmap->filemap) {
1008                         /* error or shutdown */
1009                         spin_unlock_irqrestore(&bitmap->lock, flags);
1010                         break;
1011                 }
1012
1013                 page = filemap_get_page(bitmap, j);
1014
1015                 if (page != lastpage) {
1016                         /* skip this page unless it's marked as needing cleaning */
1017                         if (!test_page_attr(bitmap, page, BITMAP_PAGE_CLEAN)) {
1018                                 int need_write = test_page_attr(bitmap, page,
1019                                                                 BITMAP_PAGE_NEEDWRITE);
1020                                 if (need_write)
1021                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
1022
1023                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1024                                 if (need_write) {
1025                                         switch (write_page(bitmap, page, 0)) {
1026                                         case 0:
1027                                                 break;
1028                                         default:
1029                                                 bitmap_file_kick(bitmap);
1030                                         }
1031                                 }
1032                                 continue;
1033                         }
1034
1035                         /* grab the new page, sync and release the old */
1036                         if (lastpage != NULL) {
1037                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1038                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1039                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1040                                         err = write_page(bitmap, lastpage, 0);
1041                                 } else {
1042                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1043                                         spin_unlock_irqrestore(&bitmap->lock, flags);
1044                                 }
1045                                 if (err)
1046                                         bitmap_file_kick(bitmap);
1047                         } else
1048                                 spin_unlock_irqrestore(&bitmap->lock, flags);
1049                         lastpage = page;
1050 /*
1051                         printk("bitmap clean at page %lu\n", j);
1052 */
1053                         spin_lock_irqsave(&bitmap->lock, flags);
1054                         clear_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1055                 }
1056                 bmc = bitmap_get_counter(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1057                                         &blocks, 0);
1058                 if (bmc) {
1059 /*
1060   if (j < 100) printk("bitmap: j=%lu, *bmc = 0x%x\n", j, *bmc);
1061 */
1062                         if (*bmc == 2) {
1063                                 *bmc=1; /* maybe clear the bit next time */
1064                                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1065                         } else if (*bmc == 1) {
1066                                 /* we can clear the bit */
1067                                 *bmc = 0;
1068                                 bitmap_count_page(bitmap, j << CHUNK_BLOCK_SHIFT(bitmap),
1069                                                   -1);
1070
1071                                 /* clear the bit */
1072                                 paddr = kmap_atomic(page, KM_USER0);
1073                                 if (bitmap->flags & BITMAP_HOSTENDIAN)
1074                                         clear_bit(file_page_offset(j), paddr);
1075                                 else
1076                                         ext2_clear_bit(file_page_offset(j), paddr);
1077                                 kunmap_atomic(paddr, KM_USER0);
1078                         }
1079                 }
1080                 spin_unlock_irqrestore(&bitmap->lock, flags);
1081         }
1082
1083         /* now sync the final page */
1084         if (lastpage != NULL) {
1085                 spin_lock_irqsave(&bitmap->lock, flags);
1086                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
1087                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1088                         spin_unlock_irqrestore(&bitmap->lock, flags);
1089                         err = write_page(bitmap, lastpage, 0);
1090                 } else {
1091                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
1092                         spin_unlock_irqrestore(&bitmap->lock, flags);
1093                 }
1094         }
1095
1096         return err;
1097 }
1098
1099 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
1100                                             sector_t offset, int *blocks,
1101                                             int create)
1102 {
1103         /* If 'create', we might release the lock and reclaim it.
1104          * The lock must have been taken with interrupts enabled.
1105          * If !create, we don't release the lock.
1106          */
1107         sector_t chunk = offset >> CHUNK_BLOCK_SHIFT(bitmap);
1108         unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
1109         unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
1110         sector_t csize;
1111
1112         if (bitmap_checkpage(bitmap, page, create) < 0) {
1113                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1114                 *blocks = csize - (offset & (csize- 1));
1115                 return NULL;
1116         }
1117         /* now locked ... */
1118
1119         if (bitmap->bp[page].hijacked) { /* hijacked pointer */
1120                 /* should we use the first or second counter field
1121                  * of the hijacked pointer? */
1122                 int hi = (pageoff > PAGE_COUNTER_MASK);
1123                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap) +
1124                                           PAGE_COUNTER_SHIFT - 1);
1125                 *blocks = csize - (offset & (csize- 1));
1126                 return  &((bitmap_counter_t *)
1127                           &bitmap->bp[page].map)[hi];
1128         } else { /* page is allocated */
1129                 csize = ((sector_t)1) << (CHUNK_BLOCK_SHIFT(bitmap));
1130                 *blocks = csize - (offset & (csize- 1));
1131                 return (bitmap_counter_t *)
1132                         &(bitmap->bp[page].map[pageoff]);
1133         }
1134 }
1135
1136 int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
1137 {
1138         if (!bitmap) return 0;
1139
1140         if (behind) {
1141                 atomic_inc(&bitmap->behind_writes);
1142                 PRINTK(KERN_DEBUG "inc write-behind count %d/%d\n",
1143                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1144         }
1145
1146         while (sectors) {
1147                 int blocks;
1148                 bitmap_counter_t *bmc;
1149
1150                 spin_lock_irq(&bitmap->lock);
1151                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 1);
1152                 if (!bmc) {
1153                         spin_unlock_irq(&bitmap->lock);
1154                         return 0;
1155                 }
1156
1157                 switch(*bmc) {
1158                 case 0:
1159                         bitmap_file_set_bit(bitmap, offset);
1160                         bitmap_count_page(bitmap,offset, 1);
1161                         blk_plug_device(bitmap->mddev->queue);
1162                         /* fall through */
1163                 case 1:
1164                         *bmc = 2;
1165                 }
1166                 BUG_ON((*bmc & COUNTER_MAX) == COUNTER_MAX);
1167                 (*bmc)++;
1168
1169                 spin_unlock_irq(&bitmap->lock);
1170
1171                 offset += blocks;
1172                 if (sectors > blocks)
1173                         sectors -= blocks;
1174                 else sectors = 0;
1175         }
1176         return 0;
1177 }
1178
1179 void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors,
1180                      int success, int behind)
1181 {
1182         if (!bitmap) return;
1183         if (behind) {
1184                 atomic_dec(&bitmap->behind_writes);
1185                 PRINTK(KERN_DEBUG "dec write-behind count %d/%d\n",
1186                   atomic_read(&bitmap->behind_writes), bitmap->max_write_behind);
1187         }
1188
1189         while (sectors) {
1190                 int blocks;
1191                 unsigned long flags;
1192                 bitmap_counter_t *bmc;
1193
1194                 spin_lock_irqsave(&bitmap->lock, flags);
1195                 bmc = bitmap_get_counter(bitmap, offset, &blocks, 0);
1196                 if (!bmc) {
1197                         spin_unlock_irqrestore(&bitmap->lock, flags);
1198                         return;
1199                 }
1200
1201                 if (!success && ! (*bmc & NEEDED_MASK))
1202                         *bmc |= NEEDED_MASK;
1203
1204                 (*bmc)--;
1205                 if (*bmc <= 2) {
1206                         set_page_attr(bitmap,
1207                                       filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1208                                       BITMAP_PAGE_CLEAN);
1209                 }
1210                 spin_unlock_irqrestore(&bitmap->lock, flags);
1211                 offset += blocks;
1212                 if (sectors > blocks)
1213                         sectors -= blocks;
1214                 else sectors = 0;
1215         }
1216 }
1217
1218 int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks,
1219                         int degraded)
1220 {
1221         bitmap_counter_t *bmc;
1222         int rv;
1223         if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
1224                 *blocks = 1024;
1225                 return 1; /* always resync if no bitmap */
1226         }
1227         spin_lock_irq(&bitmap->lock);
1228         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1229         rv = 0;
1230         if (bmc) {
1231                 /* locked */
1232                 if (RESYNC(*bmc))
1233                         rv = 1;
1234                 else if (NEEDED(*bmc)) {
1235                         rv = 1;
1236                         if (!degraded) { /* don't set/clear bits if degraded */
1237                                 *bmc |= RESYNC_MASK;
1238                                 *bmc &= ~NEEDED_MASK;
1239                         }
1240                 }
1241         }
1242         spin_unlock_irq(&bitmap->lock);
1243         return rv;
1244 }
1245
1246 void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted)
1247 {
1248         bitmap_counter_t *bmc;
1249         unsigned long flags;
1250 /*
1251         if (offset == 0) printk("bitmap_end_sync 0 (%d)\n", aborted);
1252 */      if (bitmap == NULL) {
1253                 *blocks = 1024;
1254                 return;
1255         }
1256         spin_lock_irqsave(&bitmap->lock, flags);
1257         bmc = bitmap_get_counter(bitmap, offset, blocks, 0);
1258         if (bmc == NULL)
1259                 goto unlock;
1260         /* locked */
1261 /*
1262         if (offset == 0) printk("bitmap_end sync found 0x%x, blocks %d\n", *bmc, *blocks);
1263 */
1264         if (RESYNC(*bmc)) {
1265                 *bmc &= ~RESYNC_MASK;
1266
1267                 if (!NEEDED(*bmc) && aborted)
1268                         *bmc |= NEEDED_MASK;
1269                 else {
1270                         if (*bmc <= 2) {
1271                                 set_page_attr(bitmap,
1272                                               filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap)),
1273                                               BITMAP_PAGE_CLEAN);
1274                         }
1275                 }
1276         }
1277  unlock:
1278         spin_unlock_irqrestore(&bitmap->lock, flags);
1279 }
1280
1281 void bitmap_close_sync(struct bitmap *bitmap)
1282 {
1283         /* Sync has finished, and any bitmap chunks that weren't synced
1284          * properly have been aborted.  It remains to us to clear the
1285          * RESYNC bit wherever it is still on
1286          */
1287         sector_t sector = 0;
1288         int blocks;
1289         if (!bitmap) return;
1290         while (sector < bitmap->mddev->resync_max_sectors) {
1291                 bitmap_end_sync(bitmap, sector, &blocks, 0);
1292 /*
1293                 if (sector < 500) printk("bitmap_close_sync: sec %llu blks %d\n",
1294                                          (unsigned long long)sector, blocks);
1295 */              sector += blocks;
1296         }
1297 }
1298
1299 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
1300 {
1301         /* For each chunk covered by any of these sectors, set the
1302          * counter to 1 and set resync_needed.  They should all
1303          * be 0 at this point
1304          */
1305
1306         int secs;
1307         bitmap_counter_t *bmc;
1308         spin_lock_irq(&bitmap->lock);
1309         bmc = bitmap_get_counter(bitmap, offset, &secs, 1);
1310         if (!bmc) {
1311                 spin_unlock_irq(&bitmap->lock);
1312                 return;
1313         }
1314         if (! *bmc) {
1315                 struct page *page;
1316                 *bmc = 1 | (needed?NEEDED_MASK:0);
1317                 bitmap_count_page(bitmap, offset, 1);
1318                 page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));
1319                 set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
1320         }
1321         spin_unlock_irq(&bitmap->lock);
1322
1323 }
1324
1325 /*
1326  * flush out any pending updates
1327  */
1328 void bitmap_flush(mddev_t *mddev)
1329 {
1330         struct bitmap *bitmap = mddev->bitmap;
1331         int sleep;
1332
1333         if (!bitmap) /* there was no bitmap */
1334                 return;
1335
1336         /* run the daemon_work three time to ensure everything is flushed
1337          * that can be
1338          */
1339         sleep = bitmap->daemon_sleep;
1340         bitmap->daemon_sleep = 0;
1341         bitmap_daemon_work(bitmap);
1342         bitmap_daemon_work(bitmap);
1343         bitmap_daemon_work(bitmap);
1344         bitmap->daemon_sleep = sleep;
1345         bitmap_update_sb(bitmap);
1346 }
1347
1348 /*
1349  * free memory that was allocated
1350  */
1351 static void bitmap_free(struct bitmap *bitmap)
1352 {
1353         unsigned long k, pages;
1354         struct bitmap_page *bp;
1355
1356         if (!bitmap) /* there was no bitmap */
1357                 return;
1358
1359         /* release the bitmap file and kill the daemon */
1360         bitmap_file_put(bitmap);
1361
1362         bp = bitmap->bp;
1363         pages = bitmap->pages;
1364
1365         /* free all allocated memory */
1366
1367         if (bp) /* deallocate the page memory */
1368                 for (k = 0; k < pages; k++)
1369                         if (bp[k].map && !bp[k].hijacked)
1370                                 kfree(bp[k].map);
1371         kfree(bp);
1372         kfree(bitmap);
1373 }
1374 void bitmap_destroy(mddev_t *mddev)
1375 {
1376         struct bitmap *bitmap = mddev->bitmap;
1377
1378         if (!bitmap) /* there was no bitmap */
1379                 return;
1380
1381         mddev->bitmap = NULL; /* disconnect from the md device */
1382         if (mddev->thread)
1383                 mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
1384
1385         bitmap_free(bitmap);
1386 }
1387
1388 /*
1389  * initialize the bitmap structure
1390  * if this returns an error, bitmap_destroy must be called to do clean up
1391  */
1392 int bitmap_create(mddev_t *mddev)
1393 {
1394         struct bitmap *bitmap;
1395         unsigned long blocks = mddev->resync_max_sectors;
1396         unsigned long chunks;
1397         unsigned long pages;
1398         struct file *file = mddev->bitmap_file;
1399         int err;
1400         sector_t start;
1401
1402         BUG_ON(sizeof(bitmap_super_t) != 256);
1403
1404         if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
1405                 return 0;
1406
1407         BUG_ON(file && mddev->bitmap_offset);
1408
1409         bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
1410         if (!bitmap)
1411                 return -ENOMEM;
1412
1413         spin_lock_init(&bitmap->lock);
1414         atomic_set(&bitmap->pending_writes, 0);
1415         init_waitqueue_head(&bitmap->write_wait);
1416
1417         bitmap->mddev = mddev;
1418
1419         bitmap->file = file;
1420         bitmap->offset = mddev->bitmap_offset;
1421         if (file) {
1422                 get_file(file);
1423                 do_sync_file_range(file, 0, LLONG_MAX,
1424                                    SYNC_FILE_RANGE_WAIT_BEFORE |
1425                                    SYNC_FILE_RANGE_WRITE |
1426                                    SYNC_FILE_RANGE_WAIT_AFTER);
1427         }
1428         /* read superblock from bitmap file (this sets bitmap->chunksize) */
1429         err = bitmap_read_sb(bitmap);
1430         if (err)
1431                 goto error;
1432
1433         bitmap->chunkshift = find_first_bit(&bitmap->chunksize,
1434                                         sizeof(bitmap->chunksize));
1435
1436         /* now that chunksize and chunkshift are set, we can use these macros */
1437         chunks = (blocks + CHUNK_BLOCK_RATIO(bitmap) - 1) /
1438                         CHUNK_BLOCK_RATIO(bitmap);
1439         pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;
1440
1441         BUG_ON(!pages);
1442
1443         bitmap->chunks = chunks;
1444         bitmap->pages = pages;
1445         bitmap->missing_pages = pages;
1446         bitmap->counter_bits = COUNTER_BITS;
1447
1448         bitmap->syncchunk = ~0UL;
1449
1450 #ifdef INJECT_FATAL_FAULT_1
1451         bitmap->bp = NULL;
1452 #else
1453         bitmap->bp = kzalloc(pages * sizeof(*bitmap->bp), GFP_KERNEL);
1454 #endif
1455         err = -ENOMEM;
1456         if (!bitmap->bp)
1457                 goto error;
1458
1459         /* now that we have some pages available, initialize the in-memory
1460          * bitmap from the on-disk bitmap */
1461         start = 0;
1462         if (mddev->degraded == 0
1463             || bitmap->events_cleared == mddev->events)
1464                 /* no need to keep dirty bits to optimise a re-add of a missing device */
1465                 start = mddev->recovery_cp;
1466         err = bitmap_init_from_disk(bitmap, start);
1467
1468         if (err)
1469                 goto error;
1470
1471         printk(KERN_INFO "created bitmap (%lu pages) for device %s\n",
1472                 pages, bmname(bitmap));
1473
1474         mddev->bitmap = bitmap;
1475
1476         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
1477
1478         return bitmap_update_sb(bitmap);
1479
1480  error:
1481         bitmap_free(bitmap);
1482         return err;
1483 }
1484
1485 /* the bitmap API -- for raid personalities */
1486 EXPORT_SYMBOL(bitmap_startwrite);
1487 EXPORT_SYMBOL(bitmap_endwrite);
1488 EXPORT_SYMBOL(bitmap_start_sync);
1489 EXPORT_SYMBOL(bitmap_end_sync);
1490 EXPORT_SYMBOL(bitmap_unplug);
1491 EXPORT_SYMBOL(bitmap_close_sync);